Scientists have unveiled a promising new technique that utilizes wastewater treatment processes to create valuable industrial products. This approach centers on a naturally occurring substance called extracellular polymeric substance (EPS), extracted from leftover sludge in wastewater treatment plants.
The study, published in Environmental Science and Ecotechnology, demonstrates that EPS can be used to effectively coat paper, significantly enhancing its water resistance (up to 65%), oil and grease repellency, and overall surface quality. This multi-layered coating creates a smoother and less porous surface on the paper.
Traditionally, biological treatment using activated sludge has been the mainstay for removing pollutants from wastewater. However, managing excess sludge generated during this process poses a significant challenge. Disposal costs can account for up to half of the total expenditure in wastewater treatment facilities.
This new research paves the way for a more sustainable solution. Wastewater treatment plants are shifting their focus towards recovering raw materials from excess sludge, transforming it into a potential source of renewable resources. This approach aligns with the “biorefinery” paradigm, aiming to extract valuable materials from waste streams.
The abundance of EPS in excess sludge makes it a particularly attractive target for biorefinery applications. EPS boasts a unique composition of polysaccharides, proteins, and humic-acid substances, making it a potential alternative to synthetic polymers used in various industries, such as agriculture, medicine, and construction.
The addition of EPS to the paper coating resulted in a substantial improvement in water and grease resistance. Notably, EPS derived from paper industry sludge yielded the most exceptional results. This can be attributed to its higher protein content and more hydrophobic characteristics compared to the other EPS samples.
This study establishes a groundbreaking application for EPS, demonstrating its potential as a valuable additive for paper coating, offering significant improvements in water barrier properties. From the paper industry’s perspective, the ability of EPS to enhance grease resistance and absorption is particularly noteworthy.
The successful utilization of biomaterials recovered from wastewater sludge presents a significant leap towards a more sustainable and circular economy. This research offers a cost-effective and environmentally friendly approach to wastewater management, while simultaneously creating valuable industrial products from waste materials.
